The overall goal of the Medical Structural Genomics of Pathogenic Protozoa (MSGPP) Program Project is to determine crystal structures of biomedically important proteins of pathogenic protozoa in complex with small-molecule ligands, and to use that information for accelerated drug development for treatment and prevention of the diseases caused by the ten major pathogenic organisms targeted. MSGPP is on the crossroads of the genomes sequencing and structural genomics revolutions in translating nucleotide sequence data into proteins, crystals, three-dimensional structures and protein-inhibiting compounds. This Project 3 is critical for this tightly integrated Program Project since it is at the intersection of Project 1, which will provide Ligands, and Projects, which will provide numerous MSGPP protein samples, while the major output of this Project will be crystals if protein-ligand complexes for X-ray structure determination in Project 4. We will use multiple avenues to obtain X-ray diffraction quality crystals. In a first step, several characterization steps will be performed to see how the protein can be trimmed, stabilized with ligands, provided with a low-polydispersity inducing buffer, and chemically modified. In a second step, a series of complementary approaches and in particular an integrated set of robots and databases will be applied to grow crystals in conjunction with several focused optimization methodologies. Innovative collaborations are in place for high-throughput initial crystal screening, determination of second virial coefficients, capillary crystallization robotics, and automated crystal image analysis. The entire spectrum of approaches within MSGPP is estimated to result in an overall crystallization success rate between 30 to 40% for each group of target variants.